The invention concerns a hydrodynamic torque-transfer unit, which is preferably in the form of a hydrodynamic brake. Such a brake is known from German Allowed Application (Auslegeschrift) No. 2 238 726, especially at FIG. 2. That brake is mounted in a housing surrounding a hollow space which is open to the environment so as to be subject to atmospheric pressure. Any fluid leaking out past the rotor shaft seals will first collect in this hollow space and then flow into a leakage reservoir mounted outside the housing. At the bottom of the housing, there is a feed reservoir that is more or less full of working fluid. The feed reservoir can be charged with compressed air. It is connected by a line to the external circulation system of the brake. There is another line from the leakage reservoir to the feed reservoir. The leakage reservoir can be charged, independent of the feed reservoir, with compressed air that will force the leaked fluid that has collected in the leakage reservoir through the line into the feed reservoir and hence back into the external circulation system of the brake.
As FIG. 1 of that German application shows, the leaked fluid that collects inside the housing will fall of its own weight into the feed reservoir when the feed reservoir is not being charged with compressed air. This presupposes that the feed reservoir is below the brake housing, which is not always the case.
The design illustrated in FIG. 2 of the German application will of course also be practical with the feed reservoir in another position, above the housing, for example. However, such an arrangement will necessitate additionalcontrols and more compressed air to return the leaked fluid to the feed reservoir.